The Enhanced Tubular Bells ( ETB ) are a MIDI controlled set of tubular bells I built in 2012. The instrument is composed of 12 chimes, each one with its own striker and damper to allow independent control of the notes, and can be used with any kind of device with MIDI output.

In fact, the ETB are an improved version of the Automatic Tubular Bells ( ATB ) , another MIDI controlled set of tubular bells I built 6 years before. The ATB sound was good but the mallets control system was not precise enough and it caused latency problems when striking the chimes. These latency problems were due to the imprecise system, based on toy motors, I used to move the mallets.

Despite the first version of the instrument was nice, there were some issues to solve on it, so I decided that I should build a new version to overcome those problems and make some improvements, but I had to start from the beginning and I had no time to build a new one by then. I would have to wait until I had more time.

But at the beginning of 2012 some circumstances gave me a bit more spare time, and that allowed me to start building the new instrument ( I spent arround 450 hours on it ! ). The idea was to solve the latency problems and add some improvements to the original version, and the result were the Enhanced Tubular Bells

The next is a list of the specifications I used to start with the new design, and also shows the main features of the current ETB:
- Capable of playing a full octave ( 12 bells to play the 12 semitones of an octave )
- At less 3 notes polyphony to allow playing chords ( in fact the instrument can strike up to 6 chimes simultaneously ) .
- Fast response strikers to avoid latency problems ( fast response is achieved using solenoids ) .
- Dampers to allow controlling the duration of the notes and applying other muting effects over the bells.
- MIDI interface to allow using it with any kind of MIDI controller or sequencer.
- Possibility to play melodies stored in MIDI files on an SD card.
- Friendly configuration user interface.
- Real Time Clock with backup supercap to keep time and allow using the instrument as a chime clock.

To have a fast response time and solve the latency problems I decided to use solenoids instead of motors. This gave-me a faster and more precise response when striking the bells. As you can see in the pictures I had to add some extra pieces to the solenoids to combine them with the mallets ( building precise enough pieces was one of the most difficult parts of the project ).

The solenoids and the strikers

The first version of strikers mounted on the instrument

The final version of strikers and a picture to give an idea of the size of the instrument

I also added dampers to the instrument to increase its expression posiblites. Dampers allow muting the chimes and control the duration of the notes. They can also be used to apply other effects to the bells sound.

The dampers

As control board I used the Synth Core B, the synth-controller prototyping board I created a year ago. It offered me all the resources I needed to implement MIDI, the access to the SD card, to create the user interface with the buttons and LCD and to control the other peripherals. Using this board speeded up the software and electronics development because it offered me the basic electronics and libraries I needed. The only part I had to develope from the beginning was the power board with the FETs used to move the solenoids.

The control board and the electronics

A near view ot the control unit

The intention was to use the same support and tubes of the ATB, but at the end I decided to start a new one from the beginning. As you can see in the pictures all the chimes are mounted on an unique support or tower and the control electronics is on an external box. This allows me using the electronics in another MIDI instrument projects.

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